This invention relates to a collapsible tubular container and, more particularly, to a tube formed from an impermeable laminated material and a method of producing the same.
A conventional tubular container made of polyethylene, etc. excellent in water resistance has a disadvantage in that it is susceptible to penetration or permeation of oil components or perfumes contained in its contents or to infiltration of oxygen thereinto, resulting in deterioration of the contents. Therefore, it is a usual practice to use a tubular container formed of a laminated film having an internal or intermediate impermeable layer.
However, in this case, the tubular container has a head member separately produced which is joined to the container at its one end to provide an outlet for the contents. Therefore, it cannot be expected that the container of this type may totally prevent deterioration of the contents due to permeation or penetration of the contents or due to infiltration of oxygen through the head member.
As a result, a tubular container provided at its head member with an impermeable layer has been introduced to overcome the above-mentioned disadvantage. In this case, the impermeable layer portion is produced separately from the tube body and or the head member. When the head member is formed, the impermeable layer previously prepared is placed in a cavity between the female mold and the mandrel and on the mandrel and is incorporated into the head member which is formed by filling the cavity with molten thermoplastic resin. In another example, the impermeable layer previously prepared is welded to the inside surface of the head member, which is in turn welded to the tube body. These examples are found in Japanese Pat. No. 48583/72. However, the tubular container thus produced has a disadvantage in that a thermoplastic resin layer, which welds together the head member and the tube body, is inevitably formed between the impermeable layers of the head member and the tube body, and therefore, permeation or penetration of the contents, infiltration of oxygen, permeation of perfumes, etc. may inevitably occur through the above-mentioned thermoplastic resin layer joint resulting in deterioration of the contents or the value of the products. In addition, since the impermeable layer is separately produced and the impermeable layer insert tends to be improperly positioned when the head member is welded or formed, defective products are often produced and, in addition, productivity of the tubular container is greatly decreased due to the complicated production processes.
The Japanese Pat. No. 23485/63 teaches a method of producing a thermoplastic tubular container, which closes the end of a tubular thermoplastic material by welding thereto a disc cut out of a molten thermoplastic material. The container thus produced has a disadvantage in that the body and the head member thereof is made of a material such as polyethylene, and therefore, deterioration of the contents thereof cannot be prevented and the productivity thereof is not high.